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Drinking Water Quality and Monitoring

York Region’s water is safe to drink. All water distributed to our residents by the nine cities, towns and townships in the region must meet high regulatory quality standards as legislated by the Province of Ontario.

York Region’s water is monitored around the clock to ensure it is in compliance with the Ontario Drinking Water Quality Standards, which identify more than 100 criteria for safe consumption limits, proven on the basis of medical research. These criteria are revised frequently by the Province to reflect new scientific findings or concerns.

Frequently Asked Questions

York Region provides clean, safe, reliable drinking water to more than one million people. It originates from three sources: Lake Ontario, Lake Simcoe and groundwater wells within York Region.

Approximately 80 per cent of water comes from Lake Ontario via the City of Toronto and the Region of Peel who sell treated water to York Region under long-term water supply contracts. The lake water is pumped north to York Region through large watermains. The Town of Georgina is supplied by two intakes in Lake Simcoe. The remainder of York Region’s needs are supplied by 40 wells scattered throughout the Region. Some of this water is blended with lake water.

Water is distributed to our municipalities through a network of approximately 344 kilometres of water mains. The municipalities then deliver it to users and collect money for both the supply of water and the treatment of wastewater. Some residents get their water from private wells located on their own properties.

Learn where your water comes from

Surface water — Lake Ontario:

City of Markham

Town of Richmond Hill

City of Vaughan

Groundwater:

Township of King (Nobleton, Schomberg, Ansnorveldt)

Town of Whitchurch-Stouffville (Ballantrae and Musselman’s Lake)

Town of East Gwillimbury (Mount Albert)

Surface water — Lake Ontario and Groundwater (blended together):

Town of Aurora

Town of East Gwillimbury (Holland Landing, Sharon, Queensville)

Town of Newmarket

Township of King (King City)

Town of Whitchurch-Stouffville (Stouffville)

Surface water — Lake Simcoe:

Town of Georgina (Keswick, Sutton, Lakeshore communities)

Where does my water come from
August 23, 2013 The Regional Municipality of Yorken-USThe Regional Municipality of York

York Region uses a disinfectant in water treatment processes in order to ensure that its residents get water that is protected from harmful bacteria and other microorganisms. There are two kinds of disinfectant used, depending on the area (chlorine, or the combination of chlorine and ammonia called chloramine). The dose of either disinfectant maintains "chlorine residual" which safeguards our drinking water. After treatment, water is safe for drinking and other uses.

Chlorine is used to treat the water supply in:

Ansnorveldt

Ballantrae and Musselman’s Lake

Georgina, Sutton and Keswick

Mount Albert

Nobleton

Stouffville

Chloramine is used to treat the water supply in:

Aurora

Richmond Hill

Holland Landing

King City

Markham

Newmarket

Queensville

Sharon

Schomberg

Vaughan and Kleinburg

Water purchased from the City of Toronto and the Region of Peel – approximately 90 per cent of York Region’s total supply – comes pre-treated with chlorine. The treated water is integrated with the Region’s other supplies and further chlorinated if necessary.

Water from Lake Simcoe undergoes multi-stage treatment at the Keswick and Georgina Water Treatment Plants. At these Water Treatment Plants, an intake pipe extends into the lake to draw water to the plant. Screens are in place to remove debris. Raw lake water is then passed through ultra-fine membranes that remove virtually all contaminants, including viruses.

At the Georgina Water Treatment Plant, the water also passes through ultraviolet light reactors that destroy any remaining bacteria. The water then passes through activated-carbon filter beds that take out taste and odour-causing molecules.

Finally, a chlorine residual is added to protect the water from bacteria that might reside in pipes during its journey to users.

Fish owners and kidney dialysis patients

Fish owners must be careful when using disinfected water because chloramines and chlorine can hurt the sensitive skin of fish, reptiles and amphibians. Chloramines and chlorine should be removed from the water before use in aquariums. There are tablets, drops and filters you can find at pet shops that will remove chlorine from the water.

Kidney dialysis patients must be careful when using chloraminated water. If you are on a dialysis machine, be sure to contact your physician for more information.

How does York Region disinfect my water
August 23, 2013 The Regional Municipality of Yorken-USThe Regional Municipality of York

Iron in groundwater can cause tap water to be discoloured. Municipal water is treated with a method called iron sequestration. This treatment method keeps iron from accumulating on fixtures. However, when water is heated in a hot water tank, the iron sequestration breaks down. This allows the iron to fall out and build up in the bottom of the tank. It is found more often in tanks with high water temperatures and low water usage.

Draining and flushing the hot water tank regularly will keep iron from accumulating in the home.

Occasionally, discolouration can occur in underground pipes. Watermain swabbing is an important maintenance practice, and is the most common cause of outside sources of discolouration. Staff make every effort to notify home owners in advance of maintenance work in their area. Contact your city of town for instructions on how to respond to these events.

This video shows two methods of watermain cleaning used by the Town of Newmarket to maintain and improve water quality conditions within its water distribution system.

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Why is my water a different colour
August 23, 2013 The Regional Municipality of Yorken-USThe Regional Municipality of York

There are a few reasons why your drinking water may have a slight taste or odour, the two most common are caused by sitting water and the time of year.

Sitting Water

Problem: The water has been sitting in the pipes for an extended period of time.

Solution: Open your taps for a few minutes to allow fresh water to enter your plumbing system. If your hot water has a musty odour, the hot water tank may need to be drained and flushed.

Time of Year

Problem: Lake algae can cause your water to have a musty or earthy taste and odour during late summer or early fall. When algae die, they release a harmless organic chemical that gives off a musty or earthy smell.

Solution: Municipal filters remove these problems in most cases but may not remove all mustiness in the case of extreme algae growth. York Region’s municipal water is safe to drink regardless.

The areas most commonly affected by lake algae are:

Keswick

Sutton

Vaughan

Richmond Hill

Markham

As an option to improve taste, you may choose to use a home treatment device to filter your tap water. Be sure to use and maintain as directed to keep your water clean and safe.

Why does my water have a strange taste or odour
August 23, 2013 The Regional Municipality of Yorken-USThe Regional Municipality of York

Sodium is normally found in drinking water. It usually comes from natural sources, road salt, water treatment chemicals and ion-exchange water softening units. It can be a concern for people who:

Have severe hypertension

Have congestive heart failure

Are on a sodium-restricted diet

According to federal guidelines and provincial standards, the objective for sodium is 200 milligrams per litre (mg/L). Anything over 200 mg/L will affect the taste of the water. According to the law, the local Medical Officer of Health must be notified when the sodium in our drinking water is more than 20 mg/L, at which point the officer will notify local physicians. Local physicians will advise patients on sodium-restricted diets.

“Hard” water contains calcium and magnesium carbonate. When water is “hard,” it can be difficult to lather and scale forms in pipes and appliances. Many people choose to install water softeners in their homes to reduce hardness which makes washing easier and prevents mineral buildup.

Can the level of water hardness affect my health?

There are currently no known negative health effects related to water hardness. Water softeners exchange calcium and magnesium with sodium or potassium. If this is a concern, you could consider a separate un-softened supply for cooking and drinking. Also, there are filtration units and treatments that can remove sodium from your drinking water.

Hardness Range – Milligrams per Litre of Calcium Carbonate:

Soft: 0-60

Moderately hard: 61-120

Hard: 121-180

Very hard: More than 180

Groundwater is usually harder than surface water because it travels slowly through sediments that are rich in calcium and magnesium. These sediments dissolve in the water and make it hard. Surface water in general is less likely to dissolve high concentration of minerals, but the water from Lake Simcoe and Lake Ontario tends to be hard. Therefore, the water in York Region is usually hard or very hard.

To convert to grains per gallon, multiply by 0.058417831.

Average Hardness – Milligrams per Litre of Calcium Carbonate:

Ansnorveldt

Ansnorveldt Well 2,3 Treated

118

Aurora

Aurora East Elevated Tank

138

Aurora North Elevated Tank

136

Aurora North Reservoir

135

Aurora Ridge Road Reservoir

134

Aurora South Reservoir

131

Aurora Southwest Elevated Tank

133

Ballantrae

Ballantrae/Musselmans Lake Elevated Tank

229

Georgina / Keswick

Keswick West Park Heights Reservoir

151

Keswick Woodbine Elevated Tank

149

Sutton Elevated Tank

147

Holland Landing

Holland Landing East Elevated Tank

173

King City

King City Dufferin St Elevated Tank

135

King City Elevated Tank

135

Kleinburg

Kleinburg Elevated Tank

131

Mount Albert

Mount Albert North East Elevated Tank

324

Newmarket

Newmarket Glenway Reservoir

194

Newmarket Southeast Elevated Tank (Harry Walker Parkway)

145

Newmarket West Reservoir

135

Newmarket Magna Elevated Tank

148

Nobleton

Nobleton Elevated Tank

245

Nobleton North Elevated Tank

244

Queensville and Sharon

Queensville Elevated Tank

175

Schomberg

Schomberg Elevated Tank

284

Stouffville

Stouffville Elevated Tank

347

Stouffville Reservoir (5/6 Treated)

358

Stouffville Zone 1 Elevated Tank

290

York Water System*

Richmond Hill

North Richmond Hill Elevated Tank

132

North Richmond Hill Reservoir

130

Richmond Hill Coons Road Elevated Tank 2

132

Jefferson Reservoir

130

South Richmond Hill Reservoir

130

Markham

Markham Reservoir

129

McCowan Rd PD6 Reservoir

128

Milliken Elevated Tank

128

Vaughan

North Maple Reservoir

132

South Maple Reservoir

132

East Woodbridge Elevated Tank

131

West Woodbridge Elevated Tank

130

*The York Water System receives water from Peel Region and the City of Toronto.

What is water hardness
August 23, 2013 The Regional Municipality of Yorken-USThe Regional Municipality of York

Fluoride helps prevent tooth decay and naturally exists in groundwater and food. It may also be added to some regional drinking water systems.

It is recommended by The Chief Medical Officer of Health for the province of Ontario that the level of fluoride in drinking water be between 0.6 to 0.8 parts per million (ppm). For more information about fluoride in drinking water and your health, please read the Fluoride Information Fact Sheet.

Fluoride levels are regularly monitored for each York Region drinking water system as reported in the table below:

York Region Water - 2019 Q2 Average Fluoride Content

Ansnorveldt

Ansnorveldt Well 2,3 Treated

0.25

Aurora

Aurora East Elevated Tank

0.55

Aurora North Elevated Tank

0.57

Aurora North Reservoir

0.57

Aurora Ridge Road Reservoir

0.63

Aurora South Reservoir (Break Res)

0.58

Aurora Southwest Elevated Tank

0.62

Ballantrae

Ballantrae/Musselmans Lake Elevated Tank

0.05

Georgina / Keswick

Keswick West Park Heights Reservoir

0.56

Keswick Woodbine Elevated Tank

0.57

Sutton Elevated Tank

0.58

Holland Landing

Holland Landing East Elevated Tank

0.22

King City

King City Dufferin St Elevated Tank

0.60

King City Elevated Tank

0.61

Kleinburg

Kleinburg Elevated Tank

0.64

Mount Albert

Mount Albert North East Elevated Tank

0.06

Newmarket

Newmarket Glenway Reservoir

0.18

Newmarket Magna Elevated Tank

0.51

Newmarket Southeast Elevated Tank

0.45

Newmarket West Reservoir

0.57

Nobleton

Nobleton Elevated Tank

0.13

Nobleton North Elevated Tank

0.13

Queensville and Sharon

Queensville Elevated Tank

0.21

Schomberg

Schomberg Elevated Tank

0.16

Stouffville

Stouffville Elevated Tank

0.08

Stouffville Reservoir (5/6 Treated)

< 0.05

Stouffville Zone 1 Elevated Tank

0.12

York Water System*

Richmond Hill

Jefferson Reservoir

0.67

North Richmond Hill Elevated Tank

0.66

North Richmond Hill Reservoir

0.67

Richmond Hill Coons Road Elevated Tank 2

0.66

South Richmond Hill Reservoir

0.67

Markham

Markham Reservoir

0.67

McCowan Rd PD6 Reservoir

0.61

Milliken Elevated Tank

0.57

Vaughan

West Woodbridge Elevated Tank

0.65

East Woodbridge Elevated Tank

0.68

North Maple Reservoir

0.61

South Maple Reservoir

0.63

*Slight increases of fluoride can occur in systems receiving water from both groundwater sources (naturally occurring fluoride) and water from Peel Region and/or the City of Toronto.
**The York Water System receives water from Peel Region and the City of Toronto.

How much fluoride is in my water
March 27, 2019 The Regional Municipality of Yorken-USThe Regional Municipality of York

York Region provides high quality drinking water that is safe, clean and affordable.

From a cost standpoint, bottled water is dramatically more expensive. One litre of municipally supplied tap water costs about $0.001. A litre of bottled water costs about $1.50, plus the cost to dispose of the bottle. Too often, plastic beverage containers are not recycled, ending up in landfill or the environment, taking hundreds of years to break down

Why is my water a different colour
September 26, 2017 The Regional Municipality of Yorken-USThe Regional Municipality of York

York Region implements a rigorous water quality sampling program to ensure your water is safe to drink and works to identify and correct any situation that poses a threat to the area’s drinking water. York Region will issue either a Boil Water Advisory or Drinking Water Advisory if contamination is found.

For information on Boil Water or Drinking Water Advisories, contact:

York Region's Health
Connection

Toll free 1-800-361-5653 | TTY 1-866-252-9933 for the deaf or hard of hearing

How is Water Safety Monitored?

In 2016, York Region conducted 18,489 water-safety tests and 94 facility audits. In all cases, York Region met or exceeded Ministry of the Environment and Climate Change requirements.

Boil Water Advisory,contamination,safety,risk
September 26, 2017 The Regional Municipality of Yorken-USThe Regional Municipality of York

Water Quality Reporting

Drinking Water Quality Management Standard (DWQMS)

In 2007, the Ministry of the Environment and Climate Change (MOECC) finalized its made-in-Ontario drinking water quality management framework. All drinking water systems in Ontario are required to submit an Operational Plan and be registered to the DWQMS. York Region has maintained accreditation to the DWQMS since 2008. This Standard requires utilities to prepare long-term financial plans.

ISO 9001 Quality Management

York Region's certification to the ISO 9001 standard for water operations demonstrates its continued commitment to provide safe drinking water. This internationally recognized standard of excellence focuses on quality management. All water supply and treatment plants and associated facilities, owned by York Region, are registered to ISO 9001. In order to achieve registration, an organization must establish, implement, maintain and continually improve its activities and business processes. The registration process includes evaluation and review by a third party, at least annually.

Annual Water Quality Reports

The provincial Drinking Water Systems Regulation 170/03 requires York Region to create an annual report on our drinking water systems, covering the period of January 1 to December 31. The reports describe the operation of York Region drinking water systems and drinking water quality test results.

Open Data

Open Data permits easy access to government data for public use. York Region released annual reporting data through Open Data in 2016, 2017 and 2018. The 2019 data will be released in early April, 2020.

Interactive Report Highlights

The self-service dashboard showcases interactive reporting data about each drinking water system from Open Data. Accessible formats or communication supports are available upon request. Please contact AccessYork@york.ca or call 1-877-464-9675.

Related Resources

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Drinking Water Quality and Monitoring
York Region’s water is safe for drinking and must meet these high quality standards as legislated by the Ministry of the Environment.